An SMB server was discovered on the network, and the penetration tester wants to see if the server it vulnerable. Which of the following is a relevant approach to test this?

Null sessions allow unauthenticated SMB connections that can enumerate shares and user accounts, making them a classic SMB-specific vulnerability technique, but the provided answer key does not select this option.

An Xmas scan sets the FIN, PSH, and URG TCP flags simultaneously and is used for OS fingerprinting and firewall evasion during port scanning, not for probing SMB service vulnerabilities.

An ICMP flood sends a high volume of echo request packets to the target SMB server to determine whether it is susceptible to a denial-of-service condition, which is a valid form of vulnerability assessment for service availability. By overwhelming the server with ICMP traffic, the tester can observe whether the SMB service degrades or becomes unreachable, revealing a DoS vulnerability. Note: null sessions (A) are the most recognized SMB-specific enumeration technique, and many exam references treat A as the primary SMB test - if this key marks C correct, it frames DoS resilience testing as the intended approach.

A SYN flood exploits the TCP three-way handshake by sending excessive SYN packets without completing connections to exhaust server state tables, but it is not a technique targeted specifically at SMB vulnerability assessment.